A Chinese citizen journalist who meticulously recorded details of public protests and other 'mass incidents' has begun a hunger strike in protest at his mistreatment while in police detention, a rights lawyer said on Friday. Lu Yuyu, who founded the blog "Not the News," was detained alongside his girlfriend Li Tingyu on suspicion of "picking quarrels and stirring up trouble" by police in the southwestern province of Yunnan on June 16. According to Li Tingyu's lawyer Huang Simin, he began refusing food and water in protest at alleged mistreatment in a police-run detention center in Yunnan's Dali. "[He started] on Wednesday," Huang said. Asked if he was still refusing food, she said: "I guess so." Detention center guards had twisted his arms, choked him, and that he had hit his head on a wall as a result, Huang said. "[Lu's lawyer Wang Zongyue] told me that he had injuries on his head and he couldn't sleep very well with the lights on ... and that he got into an altercation with the prison guards about this," Huang told RFA on Friday. "Even if he did break prison rules, they still shouldn't use violence to deal with it," she said. Huang said Lu's lawyer had lodged an official complaint with the state prosecutor's office and the detention center. Investigation called for The New York-based Committee to Protect Journalists (CPJ) called on the ruling Chinese Communist Party to investigate the complaints. "Given Chinese authorities' record of abusing detainees, we are troubled by the allegation that guards assaulted Lu Yuyu in custody," CPJ spokesman Robert Mahoney said in a statement on the group's website. "We call on Chinese authorities to drop the ridiculous charges against Lu and his partner Li Tingyu, and to seriously investigate the accusation," he said. Huang said Li Tingyu had heard Lu shouting "Help me! Help!" from the women's section of the detention center. "She wasn't beaten[herself]," she said. Wang said the dispute had broken out when Wang tried to cover his face with his bedding to stop the light shining on him. "He couldn't get to sleep, so he covered up his eyes, but the guards said that was against the law, or against their rules, so there was a dispute about that," he said. Beijing-based rights activist Wang Lihong said he has been following the couple's case closely. "Naturally I'm very angry about it," Wang said. "[I heard that] Lu Yuyu was covered in bruises an his arms, so he was probably beaten up pretty badly." Wang said the two had done nothing wrong. "All they did was report on things that had already happened, and they did it very carefully, confirming their sources," Wang said. "They would always have at least three sources before they confirmed an event had taken place." "They usually also made sure that there were photos or footage from the scene ... These things actually happened; there is no question of their spreading rumors," he said. "They reported on things like forced evictions," he said. Tallying 'mass incidents' Li and Lu were detained after compiling daily lists of "mass incidents" like protests and riots that are largely ignored in the country's tightly controlled state media, making the results public via Google, Twitter and Weibo, using the handle @wickedonnaa. Li, who was forced to drop out of a translation and interpretation degree at Guangzhou's prestigious Zhongshan University after publishing articles out of the reach of Chinese government internet censors, was also formally arrested on the same charges at the same time. She has told her lawyer she is innocent. She had already been targeted for "chats" with China's state security police, and withdrew from her university amid huge political pressure on the university and on her family, according to the rights website Weiquanwang. Lu, meanwhile, has been previously detained for short periods in Shanghai and Guangzhou for "illegal assembly," and began compiling statistics of public protests and unrest in October 2012. A former migrant worker, Lu called his online operation "Not the News," in an ironic nod to the widespread censorship of "sensitive" stories of mass protests by the ruling Chinese Communist Party and the media outlets under its control. Activists have said the sort of data Lu compiled, which last year including details of more than 30,000 "mass incidents" not widely reported in China, could easily have made him a target. CPJ highlighted previous cases of journalists being assaulted and abused in custody. Police beat Wang Jing -- a volunteer journalist for the human rights news website Tianwang and force-fed her when she went on hunger strike to protest her treatment after being jailed for her reporting, the group quoted her lawyer as saying. And Huang Qi, founder and editor of the Sichuan-based Tianwang rights website, reported being seriously beaten when imprisoned from 2000-2005 on subversion charges linked to his journalism, CPJ said.